To our knowledge no bacteriophages active against N. gonorrhoeae have been described. We propose to collect and screen a large number of test and indicator strains of N. gonorrhoeae representative of different geographical areas for the presence of temperate and/or virulent bacteriophages. These strains will also be tested for sensitivity to a variety of bacteriphages and bacteriocins known to have their receptor sites located in various cell wall structures. Our initial efforts will be directed to selecting both solid and liquid media which will support maximal growth and/or survival of most N. gonorrhoeae strains and to use these media in the application of standard bacteriophage methods so useful in the past in studying the bacteriophages of Escherichia coli and the Salmonella. Once isolated we will proceed to characterize the N. gonorrhoeae bacteriophages with regard to such things as host range, plaque morphology, phage morphology in the electron microscope, lysogenic and transducing potential, UV and heat inactivation, burst size and the development of host range mutants.